Apparatus for toning printing-plates.



M. A. DROITCOUR.

APPARATUS FOR TONING PRINTING PLATES.

APPLICATION FILED MAR.17,1911.

1,005,772, Patented Oct. 10, 1911.

l i i i UNITED OFFICE.

i l-[ICHEL ANDREW DROITCOUR, 0FV OAK PARK, ILLINOIS, ASSIG-NOR T0 MIEHLEi :PRINTING PRESS AND MANUFACTURING COMIANY. F CHICAGO, ILLINOIS. A.COB- -PGRATIQN OF ILLINOIS.

Specication of Letters Patent.

arPABA'r'Us non 'roNrNG rientrino-PLATES.

Patented Oct. 10, 1911.

Original application tiledvheceinbcr 15, 1910, Serial No. 597,521.Divided and this application filed March i 17, 1911. Serial No. 615,188.

ToA all wwm it'may concern;

Be it known that '1, MICHAEL A. `Dnorr- COUR, of Oak Park, in the countyof 'Cook and State of Illinois, have invented certain '5 new and usefulImprovements in Appuratus for Toning Printing-Plates; and vl herebydeclare that the following is a full, clear, and exact descriptionthereof, reference being had to the ,accompanying drawings,

I '10 which form part of this specilication.

This inventionrelates to the production of 'toned armada-ready printingplates and resides in an improved means of producing such plates.

The present application is a division of my application for process oftoning printv:ing plates tiled Uecember`15, 1910, Serial The object of`this invention is to enable printing platesto be toned withoutcrushingany of the tine lines or dots .in the printing surface thereofduring the toning peration.

In this invention I employ (l) a toning 425 member or reverse overlay todetermine the graduation'sor tones of the'printing surface of `theprinting plate; (2) a novel pressure grader to relieve pressure on thoseportions of the face of the printing plate #where such 3o pressure wouldbe liable to injure the same; and to obtain increased pressure on otherportions of the printing plate where it is necessary in order to producethe desired tones; and (3) a novel pressure plate which 85 is rovidedwith numerous recesses or channe s in its face opposed :to theback ofthe printing plate, whereby instead of the metal of thevprinting.;-p'late being compelled to ow. laterally, when underpressure, in order 4 0 to able the plate to be thinnedat those pointshere iigh lights are desu-ed, the

metal -is permitted to pass 'into minute recesses or chan els-in suchpressure plate in'the shortest 1 Y most direct way, so that the face ofthe prix g plate can be toned with very much less p ire thereon than hasheretofore been require( 1 oning process; and the liability of crushingor injuring delicate lines or dots in the printingr 5o surfaceof theprinting plate during the` toning thereot` is practically obviated.

The invention will be explained in detail with reference to theaccompanying drawings which illustrate, diagrammatcally, one [waeticalmeans embodying the invention.

ln said drawings-Figure 1A is an edge view of a reverse overlay ortoning inem# ber. Fig. 2 represents an edge view of an ordinary.printingplate. Fig. 3 is an edge view oi a -pressure plate; and Fig.` 4 is atace view thereof; Fig. 5 is a sectional View illustrating,r a printingplate, a toning member, a toning pressure grader, and a pressure plate,in a press preparatory' to the ap- 5 plicution of pressure thereto; andFig. 6 is a similar view showing the parts nmder pressure. Fig. 7 is anedgeview of the resultant toned printing plate Vremoved from' the'press, with the toning member applied `to its facerand Fig. 8 is anedge'view of the ,finished toned printing plate.

The printing plate to be toned may bean clectttype or stereoty e late 1of usual it is desired 'to have the plate when'tinally toned and readyfor use. Such plate, prior to the toning thereof, has a plane printingsurface, as indicated in Fig. 2. From this plate a reverse overlay ortoning member Q is made in any suitable manner; usually it is made ofthin sheets of paper cut and pasted'together so as tomuke this'toningmember thicker at 4the points where it is desired to have the platethinner-,nud vice versa. ln other words this reverse overlay or toningmember is made thick opposite construction, but pre era lymade 'aboutseven-thousandths of an inch thicker thanV the ports of the printingplate which it isl desired shall produce high lights in the impressionstaken therefrom,v and is made thinner opposite those iortions of theprinting plate. which it. is esired shall prodhce solids or darkershades in the impressionsi 'lhe toningmember 2 is plaeednpon the 4tat-e1of the printing/plate] and inregister therewith; and then the printing`plate is placed face downward, with the toning member beneath it, uponthe bed 5 of a suitallie press, this bed being preferably hea-ted. Thepress may be of any suitable construe tion, but should be .such that thebed 5 and platen 6 shall be kept truly parallel at all which channelsmay be about one-sixteenth of an inch dee an preferably extend parallelboth longitudinally and transversely of the pressure plate, and dividethe undei` siii'- face thereof -into minute squares or projections 3each approximately one-thirty-second of an inch square, and having theircenters approximately one-sixteenth of an inch apart. Preferably thegrooves -in the pressure plate are slightly wider at their mouths thanat bottom, thus imparting a slight taper or pyramidal shape to theprojections 3 so that any metal which may enter the channels can bewithdrawn freely therefrom. v

Preferably I intcipose between the back of the printing plate l'and thepressure plate 3, a toning pressure-grader 4 (Figs. 5 and G). Thispressure-grader may be formed like the toning member of any suitablematerial; biit l preferably make it of layers of paper graduatedaccording to the. pressure necessary to effect the desired toning of theprinting plate. This toning pre'ssure-grader supplements the action ofthe toning member 2, being made thicker where the printing platerequires more pressure to-give the desiredtone; and thinner where thesurface of the printing plate is of such a nature that pressure wouldhave a tendency to crushj or mash the saine. vIn other words, thepressure-grader 4 is a means whereby the pressure imparted by the presscan be varied in its effec-t upon the printing plate according to thesubject matter in Vsaid plate. made will protect the delicate parts ofthe printing surface of the printing plate, which excessive pressuremight injure,I and increase the pressure on the printing plato wheresuch pressure is required.

Operation: The printing plate 1, to be toned, is placed face downwardupon the bed 5 of the press, with the toning member 2 beneath it butproperly applied against its printing surface; the pressure-grader 4 isthen laid upon the printing plate and against the bac 3 is arranged orplaced above the pressuregrader with its channeled face next thepressure-grader, see Fig. 5. The said pa.

are then forcibly clamped between the press bed 5 andplaten 6; the bedbeing preferably heated to a temperature of about 3505l Thepressure-grader when properly t thereof; the pressure-plate- F.Sutlicient pressure is applied .tp cause the face of the printing plateto conform to the toning member or reverse overlay applied to .the facethereof, the printing plate being inost forcibly pressed toward thetoning member where most pressure is re uiied in order to tone theprinting plate, an to reproduce on the face thereof the tones of thetoning member or reverse overlay. Injury to the printing surface of theprinting plate is prevented because the channels in the pressure plate 3provide a ready outlet for surplus metal, and allow the inetal at'tlieback of the plate, opposite the projections on the toning member, toprotrude into said channels, as indicated in Fig. 6; and because themetal can thus crowd back into those channels or recesses there is nolateral [low of the metal in the printing plate such as has heretoforebee`n necessary when a plane surfaced pressure member was employed;hence the toning operation can be effected with very much less pressureupon the printing plate than has hitherto been required. As a result ofthis pressing operation the face of the printing plate is caused toAreversely 'conform'to the opposed surface of the toning member 2; inother words there will be slight depressions in the face of the printingplate opposite the places where the toning inenibe'i is thick; and therewill be projections l" of metal on the back of the printing plateopposite the points where its face is depressed, as indicated in Figs. 6and 7. To remove sucliprojections and {in}r inequalities from the backof the toned printing plate; the back of such plate may be shaved. asindicated in Fig. 7, while its face is still in contact with the toningmember 2; thereby reducing the back of the printing `plate to a planesurface, and making the printing plate of proper thickness for printing,while leaving the face of the printing plate toned in the desiredmanner. Fig. 7 indicates a toned printing plate re-. moved from thepress and ready for the final shaving operation; and indicates at l howthe metal luis been forced upward on the. back of the printing plateinto the channels of the pressure plate 3; and such printinT plate canbe brought to the desired thickness by shaving italong the line c-c by acutter C, or other suitable means. Afterward the toning member 2 isremov and the finishcdprinting plate, represented in Fig. 8, remains;-the surface of this -plate being toned ready for printing.

thus produce a printing plate having different-tones iii itsprinting-surface, as indicated` in Fig. 8, and during the toningoperation the surplus metal, where the pressure is greatest, instead ofhaving to flow out in all directions from beneath the edges of the flatpress platen can simply move into the ed 12o vss whether suoli pressurejmust be greater or ing plates, consisting of a toning member 4 leSS 0Ddiilnt PRIS 0f the printing plate.; l adapted to be. applied to the faceof a printbut where greater p ressure is necessary to ing plate, apressure :late having minute t tonepart o vits face I locally holditthere, channelsin its face a apted to be applied. and the metaldoesnot laterally 'flow to against the back oi tlie'printing plate,.and Ipoints where it -could damage the plate. '-1 l means for subjectingthese parts to pressure; 75 \Vhile.some printing plates might be eilwhereby the face of the printing plate is fectively toned withoutl theemployment of caused to reversely. conform to the surface thepressure-grader@ yet for fine work the 'of the tonin member and themetal on the most satisfactory results are obtained-- by l b ack of thep ate ispermitted to How or pass using the `pressureader 4,.' as thesuc'c'ess l into the channels in the face of the pressure Bo of thetonino' 'operation isf-in the main', it not plate at those points wheredisplacement; rof b altogether, ueto the toning pressure-grader metal isnecessitated in order to tonethe; 4 in combination 4with the' pressureplate' 3 printing sui-face of the printing plate in acwhich allows for'metal displacement .'witlieorclanee with thetoniiigfnieiuber. n 'f' outlateral/flow thereof. Obviously the use 3: In apparatus fo'r toningprinting sii ofthe pressure plate 3 greatly lessonsv the plates, atoning menil'ier adapted tube apamount of pressure heretofore requiredto plied to the face of a printing plate, a prestone aprintingplate,lessens the danger of y sure-grader adapted to b e applied to thecrushing the printing surface of thepriiitl back thereof, and means t'or'subjecting the ing plate' during the pressing operation; l saidparts`to. pressure sufficient to cause the 90- and removes'the danger ofdistorting g printingsui'face ofthe printing plate tol: lines iiithe-printing surface of the printing reversely conform to the toningxnember. lute by lateral How of metal thereinduring I 4r.A Apparatus fortoning printing lates, l toning operation.- consisting: of 'a toningmember adapte to be' The pressure-grader'as above stated enapplied totlieface of a printing plate, a 95 ables greater pressure to be appliedto'any pressure-grader adapted to be applied to portion of the rinting,plate where it may l the back thereof, a pressure plateliavinga bedesired, Wit out affecting the tone imchanneled surface adapted to beapplied parted t0 the rinting surface of the piintagainst the pressuregrader, and means for ing late by t e toning-member. It would subjectingsaid parts to suliicient pressure to. 100 not o to thickenthe tonin rmember to gain cause the printing surface 'of the jprintinflfA increaseof pressure at suc points becausel plate to reversely conform to the oppthe thickening ofthe toning member would surface of the, toning member.alter its toning eect upon "the printing'4 5. Apparatus. 'fortoningprinting lates, plate. But by usingiboth a toning -menilier comprisingtoning member adapte to be 10,5 and i1- pressure-grader I'can obtain themost' applied to the face of a flat surfaced printdelicate toningeffects in -the face 'of Ithe ing late, a. pressure-grader adaptedto beprinting plate and at the same' time obtain applied to the back of saidprinting plate, a any desired graduations in the pressure upon pressureplate having a channeled surface the printing plate that will facilitatethe adapted vto b e applied against the toninr. Itoning operation, andenablethe'sameto beV layer, and means for subjecting the erformedexpeditiously Aand economically arts t lpressure sullicient to cause theprintin any ordinary press, And the employment ing surface of thepi'iiiting plate to reverscly of a channeled pressure plate'inconnection` conform to. the toning member; the metal with the toningmember and pressaregradcr at the"baclc of the plate passing into the 115localizes excessive pressure on the printing .channels in the pressurelate at the points plate 'by obyiating lateral flow-ofthe metal whereldisplaccmentof tie metal is necestherein, which otherwise wouldtend-toHow l'sary toeil'ect toning o f thc-printing plate laterally anddistribute the pressure equally 'in accordance with the toning member.throughout the printing plate.' (3. The herein described apparatus for129 WhatIclaim is: toning printing plates, comprising a re' 1.In'apparatus for producing toned 'veisc overlay adapted to he applied tothe rinting plates, a toning member adapted to'l faceof a llatsurfacedprinting plate, a pres1 e applied to the printing Vsurtaceof a print isure-grader adapted to ,be applied to the ing plate, a (weledpressureplate vadaptback oflsueh printing plate., a pressure plate edto-beav plld against the back of' the having a' channeled,surfaceadapted to be printing p ate, and means for-subjecting 4applied to thep|'ess \iicgi'ader; and means ,these parts to pressure whereby the metalfor subjecting the said partsl to pressure to on the back of the plateis permitted to flow cause the -printiug surface of the printing 3oadjacent channels in the pressure plate 3; pressure plate and the faceof the' printing thus obviously overcomin 0f the metal and locallyiolding `tliepifessurface of the toning member.

sure necessary to tone the printing' plate, 2. Apparatus for'producii'igtoned print-.

or passinto the channels in' the facev of the plate -to reverselyconform' to the oppose the lateral f .iow plate is caused to reveiselyconform to the.

surface of the reverse overlay, and sur lus as my own, I afui mysignature 'in presence metal in the back of the plate to flow into oftwo witnesses. the channels in the pressure plate at those points wheredisplacement of the metal is MICHAEL ANDREW DROITCOUR' 5 necessary toeffect the toning of the printing lVitnesses:

plate. CHAS. HICK'MAN,

In testimony that I claim the foregoing PERCY G. SHAW.

